In the context of pathology material storage, an accession number typically identifies a tissue sample within a slide or a block using a format such as XX-YY-ZZZZ where XX is a prefix which identifies the lab source, YY identifies the year, and ZZZZ identifies the particular matter (or case) number. For example, a slide or a block which is labeled “SU-07-1234” indicates that the slide or block originated from a surgery (“SU”) laboratory and is the 1234th case in 2007 from that laboratory. There may be more than a single slide, or block, that has the same accession number.
When a laboratory returns loose slides and/or blocks to a facility for storage, a person at the facility manually arranges the loose slides and/or blocks into groups based on accession numbers, and then stores the groups in boxes or other containers for later retrieval.